I don't know what to do! Everytime I try to alter or copy a formula, chaos
breaks lose!

This is what happens:

1) I want to copy part of a formula from a cell to another cell, which is
blank.
2) I highlight part of the formula.
3) I click control+c
4) I click the new, empty cell so I can begin to paste
5) All of a sudden a black dotted line is circulating around that new cell,
and the other cell containing the original formula now has a solid line
around it!!
6) So I click the original cell to escape, and now my formula is missing! It
contains the location of the new cell where I just tried to paste!!!

Why does this happen??

This drives me nuts, as it happens a lot!